RemBind ™ Case Study - PFOS Z088-01 10/16 The Problem Aqueous Film Forming Foams (AFFFs) are a class of fire-fighting foams that contain per- and polyfluoroalkyl substances (PFAS). In 2009, perfluorooctane sulfonate (PFOS) was listed as a Persistent Organic Pollutant (POP) by the Stockholm Convention due to its potential toxicity effects. Most PFASs are highly soluble in water and so tend to readily leach from contaminated soil into groundwater, thus posing a potential risk to human health and the environment. In 2015, an Australian client was required to manage 1,000 tonnes of soil impacted with PFAS originating from infrastructure maintenance work at two airport sites. In this study, RemBind was used to reduce PFAS leachability in the soil to allow for safe disposal to landfill with regulatory approval. RemBind enabled the safe disposal of 1,000 tonnes of Aqueous Film Forming Foam (AFFF) impacted soil Adding RemBind to form the base of the burial pit For more information please contact: Phone: +61 (0)8 8152 9390 Email: [email protected] Website: www.ziltek.com The RemBind Solution Lab-scale trials determined that an addition rate of 5% (w/w) RemBind to the soil was adequate to reduce PFAS concentrations in soil leachates to below the target criteria of <0.2 µg/L. Soils were segregated into high and low contamination levels based on in-situ sampling and analysis for PFAS. The highly contaminated soil ‘hotspots’ were treated with RemBind using a conventional loader and excavator, with water added to achieve a 40% (w/w) final moisture content. After treatment, validation samples were sent to Australian Laboratory Services (ALS) and analysed for an extended suite of 20 PFAS compounds, including PFOS and perfluorooctanoic acid (PFOA), using LC-MS/ MS for total concentrations (mg/kg) and leachate concentrations (µg/L). Leachates were prepared using the Toxicity Characteristic Leaching Procedure (TCLP; USEPA Method 1311) at pH 5. Ziltek’s client had previously demonstrated the long-term stability of the RemBind immobolization reaction using the Multiple Extraction Procedure (MEP) based on USEPA Method 1320. This method simulates 1,000 years of stability in acid rain conditions in an improperly designed sanitary landfill situation.